Process of obtaining lubricating oils and phenols from coal tar



35 them Wit (i. e., alcohol) of not over 60% strength and by heating the mixture to a temperature of Patented Sept. 3, 1929.

UNITED STATES PATENT OFFICE.

ANTON WEINDELQOF ESSEN-RUH R, GERMANY, ASSIGNOR TO ZEGHE HATHIAS STINNES, OF 'ESSEN-BUHB, GERMANY;

PROCESS OF OBTAINING LUBRIOATING OILS AND PHENOLS FROM COAL TAB.

No Drawing. Application filed December 12, 1924; Serial No. 755,558, and in Germany December 27, 1923.

I have succeeded in discovering methods.

by means of which primary tar is separated into its components and the latter are recovered without their properties becoming altered. In the first instance the so called asphalt materials are separated from the crude primary tar by thoroughly mixing it with the double to fiourfold quantity of benzine and'then agitating the mixture at the ordinary atmospheric temperature. By

allowing the mixture tostand at the ordinary temperature or at a temperature reduced by cooling, the asphalt after a short length of time is deposited in the shape of an insoluble mass whereupon the benzine-solution is poured off and the benzine completely removed by driving it off. The liquid oils which remain as a result of distillation contain neutrat oils free from asphalt and also "contain the phenols of the primary tar. The separating of these two, the neutral oils from the henols, is then efi'ected by mixing a suflicient quantity of spirit 7075 C. After the mixture has been allowed tostand for a short time the phenols 40 are dissolved by the dilute alcohol while the neutral oils remain undissolved. The two are then separately drawn ofi. The alcohol and a part of the water are thendriven ofl' from the phenols by heating the aqueousand alcoholic solution to a temperature of about 95 C. whereby the previously dissolved phenols are precipitated. The neutral oils are also freed by heating from the slight quantities of alcohol which they have 5 taken up. Both products, .the phenols and the neutral oils, are absolutely pure and ready for use. The phenols are'preferably distilled again, especially if they are intended to be used for medicinal purposes.

of the nary temperature.

'lated anthracene, etc.)

The separation of the henols by Washing the heated mixture with diluted alcohol is only efiected in order to produce neutral oils free from phenol when such are required.

The neutral oils which are produced according to the process described in the foregoing have approximately the viscosity of watch-makers-oil. If with the object of increasing the viscosity one, distills off a small percentage of the hydrocarbons of a low boiling point for instance up to a boiling point of 220250 C. at 760 mm, oils having the viscosity of a good fatty tar oil will be obtained. By this means however the soliditying point which previously was at -8 to -10 C. is considerably increased (to about 0 (3.). Naturally this circumstance affects the 0118 when oils of very low cold test are wanted.

In order to avoid this difliculty, I add to the primary tar free from asphalt after the benzine has been driven oif, approximately double the quantity of acetone and I cool the solution and stir it well whereby yellowish and slimy masses precipitate as being non-soluble in acetone. or only. very slightly therein. The slimy material may be separated by filtration. The solution primary tar in acetone is then diluted with water at the ordinary temperature or preferably at slightly above ordi- In this manner the primary tar is completely divided into the neutral oils which separate out and phenols soluble in the acetone solution. From the neutral oils only the acetone and a small amount of water need to be driven 0E and they may be used directly as lubricating oils of a good solidifying-point (-6 to -8 C.) The dilutedsolution of the phenol in acetone is also heated until all traces of the acetone have disappeared, after which the phenols are separated from the aqueous layer.

'Other solvents which can be mixed with v water may however also be used, such as methylated spirit, ethyl alcohol. Of these solvents relatively large quantities are however required in order to dissolve the primary tarfree from asphalt. When cooling this solution in addition to the aforementioned slimy substances considerable (methysubstances will precipitate so that the yield quantities of other l have however a very in pure oil will become considerably less. Apart therefrom the oils obtained in this manner areof a less degree of viscosity, they' good solidifying point- (-10 C.) and they are transparent and of a red colour.

Thus by treating the primary tar with acetone the phenols present'therein are obtained) simultaneously and in great quantities. These phenols owing to their tendency to turn into resins are not suitable to remain in an oil used. for lubricating purposes while during the first part of the operation the slimy substances having a great detrimental effect on the solidifying point are divided out.

It has further been proved to be of advantage to free the primary tar prior to removing the asphalt therefrom from water and particularly from the light oil. The latter would make the benzine gradually less suitable to act as a means for removing the asphalt. It has also proved advantageous to drive off the fraction u to 220250 C. in addition to the light 011 as the former must in any case be distilled from the lubricating oil in order to increase the viscosity, and to then effect the removal of the asphalt by means of benzine. If the driving off is carried on to a still higher tem erature perhapsto a temperature of 320 where the decomposition of the viscous parts commences, the parts of the tar, which cannot withstand such temperatures polymerize and are also separated out during the subsequent removal of the asphalt. In this manner lubricating oils in lesser yield but of a higher capacity for resisting heat, are obtained.

Instead of the ordinary-kinds of benzines (petroleum benzine) other benzines such as primary tar benzines may be used. The latter yield a slightly less quantity of asphalt, the resulting oils are however more viscous, the yield of oil is greater, while the oils obtained therewith can only be used for ordinary and crude lubricating-purposes on account of their small contents of soft asphalt.

EwampZe.-1100 parts by weight of a primar tar obtained rom a gas generator are distilled up to a temperature up to 240, 90 parts byweight of the distillates being obtained. The residue of distillation 1010 parts by weight is dissolved in double the quantity of benzine by stirring the mixture and the latter is allowed to stand quietly for a period of 24 hours, preferably by cooling it with water or ice, whereupon the benzine solution is poured oil? from the asphalts and the benzine is distilled ofi.

From 1100 parts of primary tar the following is obtained: Y

Parts by weight. 1. Distillate up to 240 C 90 2. Asphalt =495 3. Oils free from asphalt 515 proximately 300 parts by weight of Water,

405 parts of neutral oils free from phenols, separate out. The aqueous acetone solution contains 65 parts by Weight of phenols which after driving ofi of the acetone mostly separate from the watery solution.

The 1100 parts of primary tar thus yield Per cent 1. Fraction up to 240 C 8. 1

2. Asphalt =45. 0 3. Slimy substances 4. 4. Phenols 5. 5. Lubricating onls =34.

6. Losses 2.4

At 20 C. the oil has a specific gravity of 1.03, a viscosity =8.45 Engler at 50 C., a flash point of 138 C. and a solidifying' point of 4 C.

The conditions under which the. experiments are carried out may according to requirement and to the objects for which the substances are intended, be varied Within wide ranges. The result obtained with other primary tars also vary since the quality of the primary tars chiefly depends upon the process of low temperature distillation.

The mode of separating the asphaltic material from tar, as herein described, is not claimed herein but forms the subject matter of my concurrent application 755,554.

I claim as my invention:

1. In the process of obtaining lubricating oils' and phenols from primary tar, the steps which comprise distilling the tar up to about 240 (1, adding a quantity of benzine to' the still residue in order to separate insoluble asphaltic materials from said residue, separating the insoluble materials from the benzine solution, distilling oil the benzine from said solution, adding, to the lubricating oil material remaining, a solvent for said oil material, said solvent being also miscible with water, and thereafter adding water to said so prepared solution whereby the oil is caused to separate out and the phenols remain in solution.

2. In the process of obtaining lubricating oils and phenols from primary tar, the steps which comprise mixing the tar with a quantity of benzine amounting to several. times the quantityof the tar, separating the precipitated asphaltic materials from the remaining oil, removing the benzine from the oilby distillation, adding to the oil a solvent for the oil miscible therewith and also miscible with water in suflicient quantity to disoil out of solution but leaving the phenols in solution, and thereafter separating the oil firom the aqueous layer.

3. In the process of separating lubricating oils and phenols from oils containing the same and obtained in the treatment 0 primary tar the stepswhich comprise adding to the material, which contains the lubricating oils and phenols, a solvent for the material, miscible therewith and miscible with water, adding water to the so prepared solution to throw the lubricating oils out of solution and separating oi! the aqueous layer 15 containing the phenols.

4. In the process of separating lubricating oils andphenols from oils containin the same and obtained in the treatment 0% rimary tar, the steps which comprise ad ing acetone to the material, which contains lubricating oils and phenols, in a quantity sufficient to dissolve said material, adding water to the so repared solution in order to throw out of so ution' the lubricating oils and separating ofithe aqueous layer containing the phenols.

t In testimony whereof I aflix my signaure. 2

. ANTO WEINDEL. 

